Weighing feeder



Nov; 30, 1 937.

E. E. HARPER I WEIGHING FEEDER Filed May 27, 1955 ATTORNEY Patented Nov. 30, 1937 UNITED srAras PATENT OFFICE WEIGHING FEEDER Elmer E. Harper, Kansas City, Mo. Application May 27, 1935, Serial No. 23,720

6 Claims. (c1. 221-118) The present invention relates to materialfeeding apparatus, and particularly to apparatus of this character which operates to continuously feed the material at a uniform rate measured by weight rather than by volume.

- The primary purpose of the present invention is to provide a construction of the weighing feeder type, whereby the apparatus may be effectively operated for feeding and delivering material at either a. uniform rate, or at a controlled variable rate, as may be required by varying conditions of operation.

For accomplishing this purpose I have devised an improved apparatus in which the feeding 5 mechanism operates in conjunction with a conthrough the medium of a control element responsive to the action of the scales mechanism for producing such variation of the feeding operation as is required for maintaining the scales in proper balance. This control function is accomplishedin a positive manner and serves to produce a constant, effective as well as gradual control of the feeding operation, and without in any way interfering with the proper sensitivity 5 and accuracy of the scales function, and the carrying out of the control function serves also to insure, continuously, a substantial uniformity in the discharge of the material by the operation of the feeding means at whatever rate is required. With the foregoing general objects in view, as well as various minor objects which will appear in the course of the detailed specification, the invention will now be described by reference to the accompanying drawing showing apparatus designed for practical operation in accordance with the principles of my improvements, after which the novel and patentable features of the invention will be particularly set forth and claimed.

In the drawing- Figure 1 is a central vertical sectional elevation, showing a material feeding apparatus constructed in accordance with the present inventionpand v Figure 2 is, a plan view of the same.

Referring to the details of construction shown in said drawing, a suitable cabinet or framework 5 is provided in which is mounted a small storage hopper 6 adapted to be placed in receiving relation to a larger storage-hopper lof any approdirectly beneath the mouth of the hopper 5.

The extension l4 forming the lower end or mouth portion of the hopper 6 may be fitted with an adjustable ring l5, which may be manuallyadjusted to obtain the proper space relationship between the hopper outlet and said tray l2, and secured in its adjusted position by means of set screws 16. trol mechanism through which the feeding mech- The material which is discharged from the tray l2 (when dislodged therefrom by the reciprocating movement-hereinafter referred to) is directed on to a belt conveyor by means of a pair of troughs or chutes [1, I8, which are shown as suspended by hanger-strips l9 beneath the tray l2, these chutes being of any appropriate relative size, and properly inclined to deliver the material upon the rear or receiving end of said conveyor.

This conveyor structure comprises an endless conveyor belt operating around rollers 22 in a framework 24 which carries a platform 25 underlying the top run or span of the belt. The conveyor is maintained in horizontal position by a frame member 21 having its lower end pivoted to an anchoring link 28 which is in turn pivotally anchored at 30 to a fixed portion 3! of the main framework of the apparatus. This arrangement is adapted for supporting the conveyor structure and frame member 21 upon one end of a suitable scale beam 32 in counterbalancing relation to a set of appropriate weights 33 suspended from the other end of said beam.

The conveyor belt is driven by means of a gear 35 secured to one of the belt roller shafts 34 and in turn meshing with a drive pinion 36 forming part of a speed changer unit 31, the latter being connected by a flexible shaft 38 with another speed changer unit 39 which is provided with a belt pulley 40. The belt pulley 40 is driven by a belt 4| from a pulley 42 on acountershaft 43 which is mounted in a framework 44 at approximately the same level as the feed tray l2. This shaft 43 is also provided with a cam element 45 and a pulley 46, and this pulley is driven by means of a belt 48 from a suitable motor 50, the speed of which may, if desired, be controlled by means of a suitable rheostat 52.

The cam 45 on the shaft 43 is designed to operate an eccentric member 54 adapted to engage a plate 55 pivoted at its upper end (as indicated at 56) to the framework, and formed at its lower end with a terminal portion 5! in proximity to a terminal 58 at the end of a plate Slattached to the feed tray l2. A rod 62 is attached to the plate 55 and so actuated by a coil spring 63 as to keep the terminal portion 51 engaged with the eccentric member 54 and thus maintain a gap, or spaced relationship, between'the terminals 51' and 58, as shown. The front of the feed tray i2 is also provided with a plate 65 attached to a rod 66 carrying a coil spring 61 acting as a buffer spring in connection with the reciprocating action imparted to the tray in the feeding operation, which will now be described.

When the motor is started it provides a drive through the described pulley and belt connections and flexible shaft 38 for producing a continuous and uniform travel of the conveyor belt it also drives the shaft 43 for operating the eccentric member 54 which constitutes the actuating means for producing the feeding movement of the tray l2. The throw of the eccentric member 54 does not exceed that of the normal gap between the terminals 51 and 58, and the drive across this gap is completed by means of a'control element, in

accordance with the principle of the control,

mechanism set forth in my copending application Ser. No. 20,599 filed May 9, 1935.

This control element ill may be of wedge shape as illustrated, and is supported by an upright bar or rod 12 'or the like carried by the framework 24 of the conveyor structure, whereby theelement I0 is positioned in the gap joetween the terwhich depends upon the extent to which said element id is projected into said gap. The balance of the scale mechanism is designed to be maintained by a predetermined amount of the mate= rial carried by the belt conveyor during the feeding operation.

After material has been put in the hopper and the motor has been started, since the belt conveyor is, at the beginning, substantially empty it will be overbalanced by the excess weight 33. Consequently that end ofthe scale beam carrying the control element it will rise, presenting said element in position for transmitting reciprocating movement to the tray i2 and resulting in feeding of the material from the hopper and discharging of such material'on to the conveyor. This operation will continue until a predetermined weight of material. has been deposited upon the conveyor, sufficient to balance the scale beam;

(iii

this causes the feeding action to stop by withdrawal of the control element Hi from operative or driving position. Again, as soon as discharge of material takes place, by delivery of the material from the front or discharge end of the conveyor, this diminishes the load on the conveyor,

causing it to rise and again raising the control element and thus causing the feeding operation to be resumed until the scale balance is restored.

In fact there will be more or less of a vertical surging, or hunting, action of the conveyor at the outset, due to the material not being uni,- formly distributed on the belt; but this surging gradually dies down as the belt becomes uniformly loaded, after which the control element will operate to feed from the hopper just the right quantity of material necessary for the purpose of maintaining the scale beam in proper.

balance.

After the operation has been thus started, the rate of feed will be governed primarily by the speed at which the belt travels, and this speed may be regulated in any desired manner, one convenient method being that illustrated, by means of a rheostat control 15 for governing the speed of the motor; other types of speed changing mechanism may, however, be employed to suit conditions of operation. Still another method of controlling the rate of feed could be introduced by simply varying the load'represented by the weights 33, thereby disturbing the scale balance and producing a corresponding influence on the control device 10 for regulating the feeding operation.

Thus a weighing feeder is provided in which the material may be fed from the hopper and delivered by the conveyor at either a uniform rate, or at a controlled variable rate as conditions may require. trol feature as involved in the operation of the control element ill, and its advantages as applied to'a material feeding operation, are quite pronounced. The manner of using this control element in the apparatus which I have described, by attaching it to the conveyor structure which is in turn supported by the scale mechanism (so that the control deviceis itself a part of the balancing load on the scales), obviously offers not the slightest interference with the normal operation of the scales, and the scale mechanism is not required to perform any other mechanical function (for carrying out the control function) which would inany way interfere with the sensitivity or accurany of thescale function,an objection which does in fact apply to some other types of weighing feeders, as for example, where the movement of the scales mechanism is required The points of merit of the unique conto mechanically operate a control gate or other mechanism for regulating the amount of material supplied to the conveying or delivery mechanism.

\ Accordingly, it will be noted that the present improved construction is such as to relieve the scales mechanism entirely of any particular stresses other than those due to the exercise ofthe normal scales function,-the control element being fully released and free to move after each operating impulse, and the flexible drive shaft arrangement for the conveyor permitting considerable vertical movement of the conveyor without offering any interference with the proper performance of the scale mechanism or with the proper operation of the control function of the wedge member it. Again, the control action is not only positive but gradual, which gives a continuous and uniform feed action without any sudden starting or stopping of the flow of material from the feeder.

One special advantage of equipment provided with controlled feeding means of this type is the fact that it is particularly well adapted for automatic proportional control, as where the purpose for which the mamrial is being handled requires the amount of material delivered by the feeder to be automatically controlled in proportion to some other mechanical function in accordance with which it is desired to govern the delivery oper- F the amount of material delivered by the feeding 75 ceptible lag, from the time it is withdrawn from the hopper until it is deposited upon the belt. The arrangement of the chutes is designed to direct the material to a definite section of the belt,

at its rear or receiving end. a baflle member (such as an upright plate 11) being preferably located at this end of the conveyor in position for effectively aiding the proper distribution of the material across this portion of the conveyor. The arrangement herein shown for the chutes provides for their participation in the movement of the feeding tray [2 (as a part of the feeding mechanism), although it will be understood that for materially greater distances between said tray and the top of the conveyor belt, such movement of the chutes may not be necessary, since their angle or pitch might then-be such as to require no vibrating action of the chutes in order to discharge the material properly to the conveyor.

It will also be readily understood that the utility' of the present improvements is not confined to the feeding of 'any particular character of materials, such as dry materials in the form of construction herein illustrated; for the nature of the present invention-is such as to adapt its operation with equal facility to the feeding of liquid materials, the only modification necessary being with reference to the specific character of the feeding device and the conveyor for thehandling of liquid instead of dry or granular material, as for example a construction on the order of that shown in my copending application above referred to. I

It will thus be apparent that I have devised a practical and comparatively simple, but eflicient and highly accurate form of apparatus for the purposes of feeding weighed quantities of materials, at either a uniform rate or at an effectually controlled variable rate, according to the requirements of the particular installation; and while I have herein shown one practical form-of construction for illustrative purposes, it is obvious that the same is susceptible of wide variation or modifications, while still coming within the scope and principle of operation comprising the essential features of my invention. I therefore desire to be understood as reserving the right to all such changes or modifications which may fairly said feeding mechanism, an actuating means and a control member actuated by fluctuations in said scales-mechanism for effecting such regulation of the operation of said feeding mechanism as will maintain the scales in balanced condition, said control member being mounted for intermittent engagement with said actuating means and feeding mechanisnr while free to move between successive driving impulses for allowing said control member entirely idle .and independent adjusting movement in response to fluctuations of said scales 7 mechanism.

2. A weighing feeder construction comprising, in combination with a material-supply container, material-feeding mechanism for feeding material from said container, a scales mechanism, a conveyor supportedon said scales mechanism and operating to deliver the material as fed thereto by said feeding mechanism, and driving means for actuating both said conveyor and said feeding mechanism and including a suitable drive connection to the conveyor and also a control element responsive to fluctuations in said scales mechanism for effecting such regulation of the operation of said feeding mechanism as to maintain the scales in balanced condition; said control element mounted for intermittent engagement with said driving means and feeding mechanism while free to move between successive driving impulses for allowing said control element entirely idle and independent adjusting movement in response to fluctuations of said scales mechanism.

3. A weighing feeder construction comprising, in combination with a material-supply container, material-feeding mechanism for feeding material from said container, a scales mechanism, a conveyor supported on said scales mechanism and operating to deliver the material as fed thereto by said feeding mechanism, actuating means for said feeding mechanism, and a control member directly actuated by fluctuations in said scales mechanism for interposing said member as a variable drive connection between said actuating means and said material-feeding mechanism.

4. A weighing feeder construction comprising, in combination, a material-supply container, a conveyor operatively arranged beneath said container for delivering the material as discharged from the container, scales mechanism supporting said conveyor, a reciprocating feed tray for feeding the material from said container on to said conveyor, and a pair of chutes arranged in cooperative relation with their discharge ends spaced at predetermined distance apart for directing. the material as discharged from said tray uniformly upon a given section of said conveyor.

5. A weighing feeder construction comprising, in combination, a material-supply container, a conveyor operatively arranged beneath said container for delivering the material as discharged from the container, scales mechanism supporting said conveyor, a reciprocating feed tray for feeding the material from said container ontosaid conveyor, and a pair of oppositely inclined chutes having their lower discharge ends spaced a predetermined distance apartfor directing the material as discharged from said tray uniformly upon a. given section of said conveyor.

6. Control mechanism comprising, in combination with'a material supply container, at scales mechanism, a conveyor supported on said scales mechanism in position for receiving material as discharged from the container, means for feeding material from the container onto said conveyor and including a driven member having an abutment element, an actuating means provided with a reciprocating abutment element in spaced relation to said first element, and a controlelement responsive to. fluctuations of said scales mechanism and located between said abutment elements for constituting a variable drive abutment between said actuating means and said driven member.

ELMER E. HARPER. 

